Method and apparatus for forming flexible tubing



June 18, 1957 T. M. N. WOOD 2,796,109

METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed April 6, 1953 8 Sheets-Sheet 1 Fig. 1

' 'ATTORNEYS I June 18, 1957 T. M. N. WOOD 2,796, 09

METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed April s, 1953 4 s SheetsSheet 2 Fig. 2

INVENTOR.

ATTORNEYS T. M. N. WOOD June 18, 1957 8 Sheets-Sheet 5 Filed April 6, 1953 mmo v INVENTOR. THOMAS M. N. vyooo ATTORNEYS June 18, 1957 T. M. N. WOOD T 2,796,109

METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed April 6, 1953 8 Sheets-Sheet 4 Fig. 5.

T INVENTOR. THOMAS M.N. WOOD ATTORNEYS June 18, 1957 'r. M. N. WOOD METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed Apl il 6, 1953 8 Sheets-Sheet 5 D m mw Z5 M H24 VM. s A M E 8 m T W V. B q mo I 8 Q s H I H H I m 09 t 1 mm 3 1| 3 mg N2 mt o: v9 mm.

I Hm ATTORNEYS June 18, 1957 T. M. N. WOOD 2,796,109

METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed April 6, 1953 8 Sheets-Sheet 6 Fig. 9

- fivm ATTORNEYS T. M. N. WOOD June 18, 1957 METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed April 6 1953 8 Sheets-Sheet 7 EUMM E SE 1 Q E am moo

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INVENTOR. THOMAS M. N.WOOD

BY I y ATTORNEYS June 18, 1957 T. M.-N. WOOD METHOD AND APPARATUS FOR FORMING FLEXIBLE TUBING Filed April 6, 1953 8 Sheets-Sheet 8 AC UL OIL ACCUM- WATER SOURCE ULATOR SOUCE LI|A q l l mlm o w 8 9 2 3 O Q C C m W W M Y ms H 6 T Y B ATTORNEYS United States Patent METHOD AND APPARATUS FOR FORNIING FLEXIBLE TUBING Thomas M. N. Wood, Foxboro, Mass, assignor to Standard-Thomson Corporation, Boston, Mass, a corporation of Delaware Application April 6, 1953, Serial No. 347,093

12 Claims. (Cl. 153-73) The present invention relates to hydraulic forming machinery, and more particularly to a method and apparatus for forming folds or convolutions in straight lengths of metal tubing to render them flexible. Flexible tubing of this type has many uses, for example to provide flexible hydraulic connections or fluid conduits.

The forming machine, according to this invention, utilizes an hydraulic method of the type heretofore used in the manufacture of metal bellows of various kinds for use as flexible connectors or in temperature or pressure regulated valves, switches and similar devices. For such purposes, bellows of relatively short length are suitable. The total number of convolutions for each bellows is not normally very large, and in many cases the entire bellows may be formed in a single cycle of the forming machine.

Essentially, the method referred to involves first applying fiuid pressure to the inside of a length of straight tubing, whereby the tubing is bulged outwardly between spaced annular forming plates to partially form the convolutions, then compressing the tubing axially to complete the convolutions while retaining the forming pressure within the tubing. One or more convolutions may be formed at a time according to this process, depending upon the number of forming plates used.

A principal feature of the present invention relates to the production of relatively long lengths of flexible hose or tubing by a process similar to the above. However, owing to the considerable lengths in which the tubing is formed, it is not feasible to form all of the convolutions at one time as required by existing methods. Instead, convolutions are formed progressively, a few at a time, starting at one end and moving progressively down the length of the straight tubing, which is fed into the machine from one end.

An object of the invention is to provide an arrangementof structures adapted for forming the convolutions and for feeding the tubing progressively.

Another object is to provide hydraulic motive power to the various parts of the apparatus under the control of valves, whereby the machine may be operated in cycles, a group of convolutions being formed during each cycle, under the control of cycling means including relays, solenoid-actuated valves, limit switches and similar devices.

A further object of the invention is to provide means for properly adjusting the limits of movement of the various parts and the timing thereof in relation to the other parts.

Another feature of the invention resides in the use of carriage means for quickly and conveniently removing formed sections of tubing with a minimum of interference with the parts related to the forming operation.

Other features of the invention adapted to satisfy the above objects and others hereinafter described comprise certain structures, relationships, procedures of operation and controls hereinafter more fully described and particularly defined in the claims.

In the drawings,

Fig. 1 is a plan view partly in section of a portion of ice 2 the machine according to the present invention, including the parts related to the forming operation;

Fig. 2 is a side view of the apparatus shown in' Fig. 1;

Fig. 3 is an end elevation taken along the section line shown in Fig. 2, giving details of the book construction;

Fig. 4 is a plan view of the portion of .the machine omitted from Fig. 1, slightly reduced in scale; v I

Fig. 5 is a side view of the parts shown in Fig.4; I

Figs. 6 and 7 are enlarged side views, partly in section, taken along the section line shown in Fig. 4, and showing two positions of the apparatus associated with the removal of formed sections of tubing; j i

Fig. 8 is a detail view showing a partially formed see tion of tubing;

Fig. 9 is a schematic electrical diagram of the hydraulic valve solenoid circuits;

Fig. 10 is a schematic diagram of the control relay circuits; and

Fig. 11 is a schematic diagram of the hydraulic connections.

Referring first to Figs. 1 and 2, a rigid frame 2 forms the principal support for the parts associated with the forming operation. As shown in Figs. 4 and 5, a pair of rails 4 are secured to the frame, the rails extending back to and being supported by fixed posts 6 placed at intervals along the remaining length of the machine.

The frame 2 comprises a bed and three vertical supports 8, 10 and 12 integral therewith. The support 10 divides the frame into two main sections, the book section to the left and the driving cylinder section to the right. The straight tubing to be formed is fed into the machine from the left end at 14 through a clamping device 16 held in the support 8.

A book assembly 18 carries the forming plates for externally constraining the tubing while under pressure, and also related parts. It is free to move lengthwise of the machine along ways 20. The specific details of the construction of the assembly 18 are hereinafter more fully described, especially with reference to Fig. 3. It will be noted that the sole means for moving the assembly along the ways comprises a cylinder 22 projecting through a hole in the support 10 of the frame.

The cylinder 22 is rigidly secured to a piston 24 mounted within a cylindrical portion of a cylinder frame 26. The frame 26 is formed of three cylinders, two forming cylinders 28 and 30, and a pick-up cylinder 32. The outer cylinders 28 and 30 are supported for axial movement relative to fixed pistons which are secured to rods 34 rigidly secured at their ends to the supports 10 and 12. Motion may be transmitted to the cylinder 22 by application of pressure either to the forming cylinders 28 and 30 or to the pick-up cylinder '32. Motion may also be transmitted from the frame 26 to a pair of rods 36 (see also Fig. 4), these rods being engageable at their extreme right ends with other parts of the machine, as shown for example in Figs. 6 and 7 and hereinafter more fully described.

As shown in Fig. 1, the cylinder 22 extends through the pick-up cylinder 32 and bears a sleeve member 38 having adjustable projections for actuating a pair of limit switches LS2 and LS6. The switch LS6 is actuated when pressure is applied to a connection C17 (Fig. 2), applying pressure to the pick-up cylinder 32 to drive the cylinder 22 to the left relative to the cylinder frame 26, and the switch LS2 is similarly actuated when pressure is applied to the connection C12. Pressure applied to the connections C19 and C20 (Fig. 1) drives the frame 26 to the left, this motion'being limited by a positive stop 40 secured to the support 10 (Fig. 2). A limit switch LS3 is actuated upon the frame 26 reaching its extreme left position, a limit switch LS4 is actuated when the frame reaches its extreme right position, and a switch LS5 is actuated by an extended projection 42 of the frame 26, which holds the switch in the actuated condition at all times while the frame 26 is within a certain distance of the left-hand stop.

It will be noted that the formed sections of tubing move toward the right from the book assembly, passing through the cylinder 22 and out toward the right, the inside of the cylinder 22 being sufficiently large to permit free passage.

Figs. 1, 2 and 3 show the structure of the book assembly 18. This assembly is supported on slides 44 resting upon the ways 20; The slides are integral with vertical end walls 46, thereby forming a rigid frame within which the movable parts are supported.

immediately inside the walls 46 are vertical end plates 48 hinged about a shaft 52 which is secured in the end walls 46 as shown in Fig, 2. The plates may be rotated to the position shown in Fig. 3, in which abutments 50 are brought to res-t against spring-loaded stops on the slides 44. The two plates 48 on each side of the hinge are securely tied together at their upper and lower eX- tremities by heavy bars 53 shown in outline in Fig. 3. A pair of rods 54 passing through the forming plates are also secured between the plates 48. The frame comprising the plates 48, the shaft 52, the bars 53, and the rods 54 is referred to herein as the book frame. This "frame may be opened or closed around the tubing stock by application of pressure to a book cylinder 56. In Fig. 3 the book is shown in the open position, which corre sponds to the application of hydraulic pressure to the connection C23 of the cylinder 56. When the book is closed the plates 48 are brought into contact at their upper extremities, and proper closure of the plates is assured by machined stops 58 in :the upper portions of the plates. A pair of limit switches LS7 and LS8 are actuated when the book is in the open position, as shown in Fig. 3. To secure the book in the closed posit-ion, one plate 48 on each end (shown on the right side in Fig. 3) is formed with a square projection having a hole 60 which becomes aligned with a hole 62 in the opposite plate. A rod may then be inserted through the holes 60 and 62 after the book is closed. In the described embodiment, however, it has been found that the use of a locking rod of this type is not necessary under normal conditions since, as hereinafter shown, the forming plates are themselves provided with a locking device which is sufficiently strong to withstand the forming pressure. In the hydraulic diagram (*Fig. 11) connections C24 and C30 are shown for the purpose of indicating how hydraulic connections may be made to a cylinder (not shown) for moving the locking rod (also not shown), but it will be assumed hereinafter that the hand valves leading to these connections are and remain closed.

As noted above, a number of forming plates 64 are slidably supported on the rods 54 secured in the end plates 48 of the book frame. The forming plates are similarly supported on the shaft 52 as shown in Fig. 3. these supports cause the forming plates to open and close With the book, they do not prevent the plates from sliding axially.

Means for restricting the movements of the plates along the rods 54 and the shaft 52 are provided by sets of stepped plates adapted to cooperate :with steps in the forming plates which vary in depth by steps from one forming plate to the next adjacent plate. Referring to Figs, 1, 2 and 3, a first set comprising two pairs of plates 66 on each side are rigidly secured between the end plates 48 of the book frame; These plates are viewed obliquely in Figs. 1 and 2, their true sections being shown in Fig, 3. They restrict the leftward movement of each of the forming plates within the book frame, the limiting positions being shown in Figs. 1 and 2, but they do not prevent the forming plates from moving from these positions towards the right within the book frame.

A second set comprising two pairs of stepped plates 68 on each side of the book frame are secured upon rectanguiar slides 70. The slides 70 slide freely through the end -While walls 46 of the book assembly and are provided at their right ends with adjustable stops 72, whereby the rightward movement of each set of plates 68 is limited by the contact of a stop 72 with the vertical support 10 of the frame 2. Thus, unless the stops 72 are resting against the vertical support 10, the plates 68 ofier no restriction to the movement of the forming plates.

The manner in which the stepped plates 68 operate to limit the movement of the forming plates involves a discussion of the forming operation which is hereinafter described in further detail.

When the book is closed the forming plates are closed in pairs, each pair meshing by means of semi-circular projections 74 (Fig. 3). Each pair of forming plates is then locked together by means of a toggle link assembly comprising a forked link 76, secured at one end to each righthand forming plate, and at the other end to a toggle link 7 8, the link 78 being adapted to fit securely in the locked position against a formed surface 80 on the opposite plate. This type of locking device is well known in the art and makes use of a curved surface of the link 78 adjacent to the connection with the link 76 and eccentric therewith, whereby, as the links 76 and 78 are rotated by an arm 82 until they fall in line, a progressive pressure is applied to the surface 80. The arm 82 is coupled through intermediate links and bevel gears 84 to a plate locking piston 86 (Fig. 2).

The end plates 48 of the book frame on one side (the left side in Fig. 3) support a pair of guide bars 88 rigidly secured thereto. These bars slidably support a spacer slide 90 having secured thereto in fixed, spaced relationship, a set of spacers 92 having curved edges adapted to close around the unformed section of tubing with a clearance, as shown in Fig. 8, for bulging of the tubing, By means of linkages shown in Fig. 3 the slide 90 may be inserted or retracted along the rods 88 by applying pres sure to a spacer cylinder 94. When the spacers are fully inserted a limit switch L810 is actuated, and when fully retracted, a limit switch LS9 is actuated. These spacers are adapted for insertion between [the forming plates 64 and serve to hold the forming plates in rigid relationship during the initial stage of the forming operation. They are retracted immediately afiter the convolutions have been partially formed so as to allow the spacer plates to be pressed together to form the completed convolutions.

A chuck comprising three meshing, wedge-shaped seg ments 96, having surfaces con-forming with the completed convolutions, is adapted to grasp the most recently formed section of tubing While the succeeding section is being "formed. Each chuck segment is provided with a slide block adapted to slide in a stationary slot 98 in a flanged end section of the cylinder 22. A short slide pin 100 projects from the slide block into a slot 102 in a plate 104 supported for rotation about the cylinder 22 by a pair of arms 106. The chuck segment is moved toward or away from its closed position, depending upon the angular posiltlOl'l of the plate 104 whichis controlled, through intermediate linkages, by a chuck cylinder 108. A limit switch L516 is actuated when the chuck is open, and a limit switch LS1 is actuated when the chuck is closed.

Inside the cylinder 22 and the tubing itself, there are two concentric, hollow shafts or tubes and 112 (Fig. 1) which are used to seal the tubing during the forming operation and to apply the hydraulic forming pressure thereto. These cylinders extend almost the entire length of the machine and are moved by mechanism at their right end extremities in a manner hereinafter described. However, at this point the structure of the associated parts shown more particularly in Fig. 8 may be noted. In Fig. 1 the tubes 110 and 112 are shown in their positions immediately prior to the beginning of a forming operation, and as shown in Fig. 8 they remain in the same positions while the pressure is being applied to the tubing. The tube 112 is provided with a nose piece 114 slightly clearing the unformed section of tubing, but having an O-ring 115 which seals the tubing on application of fluid pressure behind the nosepiece through an orifice 116. The fluid, preferably water under pressure, floods the section of tubing between the nosepiece 114 and a rubber seal 118. The seal 118 expands against the chuck jaws upon application of the pressure by compression between the tube 110 and a spring-loaded sliding element received therein.

The tubing is firmly clamped at the nosepiece 114 by the tube clamp assembly shown in Fig. 1. This assembly includes a fixed outer sleeve 120 supported in the vertical support 8 of the frame 2, inside of which is slidably supported a sleeve 122. A ring of rubber or similar material 124 is inserted at the right end of the sleeve 122 as shown in Fig. 8, whereby it is possible by sliding the sleeve 122 to the right to compress the ring against the tubing. This clamping action is effected through the tube clamp cylinder 16, to which hydraulic pressure may be applied through connections C13 or C14, as shown in Fig. 2.

It will be noted that the various structures mounted upon the frame 2 and heretofore described comprise all of the parts necessary to form the convolutions in the tubing. The number of convolutions formed at one time depends upon the number of forming plates 64 which are employed. It will be apparent that many factors will affect the number of forming plates used, for example, the physical limits of the space between the end plates 48 of the book frame, and the required depth of the finished convolutions. The latter factor also affects the space between adjacent forming plates. The machine is readily adapted for the use of different sets of forming plates and spacers depending upon the diameter of the tube stock and the depth of the convolutions. It will be noted that changes in the forming plates will also necessitate changing the stepped plates 66 and 68 in some instances, which may also be readily accomplished.

Figs. 4, 5, 6 and 7 show the portion of the machine relating to the removal of formed sections of tubing. This structure is supported on the rails 4 which are rigidly secured at one end to the frame 2 and at intermediate points along their length to the fixed posts 6.

The moving parts in this assembly are mainly supported upon a carriage 126 provided with wheels 128 rolling.

on the rails 4. In the position shown in Fig. 5 in solid lines the carriage is resting on a horizontal section of the rails 4; but it may be rolled back into the position shown in dot-dash lines, wherein the wheels at the extreme right end are lowered by reason of a depression in the rails 4. The resultant tilt of the carriage provides a means for raising the formed section of tubing over the top of the forming apparatus at the other end of the machine.

As shown in Figs. 5 and 6, the carriage 126 is in its extreme left-hand position, where it is locked to a post 6 by a pin 138 extending from a projection at its left end. A locking shoe 132 having a fixed pivot may be locked in the position shown by application of hydraulic pressure to a carriage locking piston 134.

Slidably supported upon the carriage 126 is a subcarriage 136, to which is pivoted at its lower extremity a rack 138 adapted to be moved horizontally over a roller 140 extending from a projection of the carriage 126. As shown in Fig. 7, when the carriage 126 is not locked in its left-hand position, a spring 142 forces a block 144 into mesh with the rack 140. Since the block 144 is pivoted to an extension of the carriage 126, this locks: the sub-carriage 136 relative to the carriage 126. A rod 146 passing through the block is supported in a pivoted member 148, and spring-loaded to permit the block to slip easily into engagement with the rack 140- in spite of slight differences in the alignment of the teeth.

As the carriage 126 is moved towards the left from the position shown in Fig. 7, the member 148 makes contact with the locking shoe 132 and is rotated upward as the shoe is rotated into the locked position, thereby disengaging the block 144 from the rack 138, and thereafter permitting the sub-carriage 136 to be moved rela tive to the carriage 126.

As shown in Fig. 4, the inner tube 112 discussed above with reference to Fig. 8 extends to a support block 150 on the carriage 126 having a pair of spanner nuts 152 for locking a threaded sleeve 154 secured to the tube 112. This arrangement provides means for accurately locating the nosepiece 114 (Fig. 8) when the carriage 126 is .locked in the position shown in Fig. 6. The tube 112 extends through the tube 110 which is similarly supported in a block 156, integral with the sub-carriage 136.

A pair of swivel brackets 158 (Figs. 4 and 7) are screwed to the block 156. These brackets pivotally support a pair of rods 160 to which are secured a pair of locking sleeves 162. The rods 160 extend through the locking sleeves 162 and are secured to pistons 164 in a pair of carriage operating cylinders 166. These cylinders are secured to the rods 36 which are securely connected with the cylinder frame 26 as discussed above with reference to Fig. 1. As shown in Figs. 6 and 7, the cylinders 166 are slidably supported on the rails 4 by sleeves 168.

Devices for locking the rods 160 to the cylinders 166 are secured to the ends of the cylinders, and comprise outer sleeves 170 and inner sleeves 172, which are relatively movable to lock a set of ball bearings behind the locking sleeves 162 (see Fig. 6), or to free the ball bearings therefrom by allowing them to fall into recesses in the outer sleeves 170 (see Fig. 7). Pistons 174 (Fig. 4) are provided for moving the sleeves 172 relative to the sleeves 170. The connections for applying hydraulic pressure to the pistons 174 are C1, C6, C2, and C7.

Referring to Fig. 5, a wheel support 176 is pivoted on an arm 178 secured to a post 6, the arm 178 having an upward extension to which is firmly secured a magnet S20 having an armature 180 adapted to cooperate with a cam surface 182, also secured to the post 6. Upon application of hydraulic pressure to a wheel operating cylinder 184, a pair of links 186 and 188 are brought into alignment, thereby removing the link 186 from contact with a fixed stop 190. The wheel then reaches the position shown in dash-dot lines in Fig. 5. A support roller 192 is connected by an intermediate link to the arm 178, and is further connected by a toggle arrangement with the armature 180 of the magnet S20. The toggle is arranged so that as the wheel 176 is raised to its upper position the armature 180' snaps and locks the toggle so that the roller 192 is in turn locked into a position slightly raised from that'shown in Fig. 5, whereby when'the wheel 176 is again lowered the tube 110 is eventually brought to rest against the roller rather than against the Wheel 176.

After the tube 110 is again lowered into position, anew section of tubing is formed, and eventually projects to a position Where it actuates a limit switch LS14 opposite the wheel 176. As shown in Fig. 10, this switch energizes a relay R20, a contact of which energizes the magnet S20 (see Fig. 9) to unlock the toggle and to bring the armature 180 to the position shown in Fig. 5, whereby the roller 192 is lowered sufficiently to permit the formed convolutions of tubing to pass it without making any contact. It will be noted that the wheel 176 for lifting the tube 110 and the formed tubing is well adapted to prevent any injury to the tubing when removing it from the machine.

Operation-general drical stops 194 abutting against the vertical support 12 of the frame 2. Similarly, the piston 24 is at the extreme right end of, the pick-up cylinder 32 and the book carriage 18 is in its extreme right position with the stop 72 resting against the vertical support 10. In this position, the forming plates 64 are held in accurate spaced relationship by the stepped plates 66 and 68 which are pressing against their opposite sides. The book frame is in the open position, and the chuck is closed.

The chuck is first opened, and an unformed section of tubing 14 is inserted through the tube clamp until it passes beneath the chuck segments 96. The tube clamp cylinder 16 is then actuated to' hold the tube near the nosepiece 114 and the chuck is again closed.

Next, the book frame is closed, thereby bringing the forming plates into close contact with the outside of the unformed tubing. The spacers are then inserted between the forming plates, whereupon, the plates are locked and fluid pressure is applied to the tube 112. The fluid pressure forms a seal both at the nosepiece 114 and at the seal 118.

As shown in Fig. 8, the pressure expands the tubing outward against the forming plates to form the convolutions partially, in the spaces between the forming plates. Next, the spacers are removed from between the forming plates by retracting the slide 90.

The forming cylinders 28 and 30 are then supplied with hydraulic pressure at the connections C19 and C20, moving the cylinder 22 to the left. The end flange of the cylinder 22 bears directly upon the end walls 46 of the book assembly, and the chuck 96 moves to the left with the seal 118 and the tube 110, the latter tube being connected to the cylinder frame 26 through the rods 36 and the support block 156 of the sub-carriage 136. As heretofore noted, the sub-carriage 136 is free to move toward the left, due to its disengagement from the carriage 126 while the latter is locked in its extreme left position.

During this movement of the book carriage the forming plates become closely stacked, since the tubing is held fixed at the nosepiece 114. In other words, as the book carriage moves to the left the tubing is held fixed at a point immediately to the left of the partially formed convolutions, the chuck 96 compresses the right end of the tubing toward the left, and the forming plates 64, being held between the partially formed convolutions, are gradually drawn closer together. The stepped plates 66 and 68 permit this, since the stops 66 move to the left with the book carriage, while the stops 68 are free to remain behind as the carriage moves to the left.

It will also be noted that during this movement the fluid pressure within the tubing is retained until the convolutions are completely formed.

The next step is to remove the fluid pressure from inside the formed section of tubing while moving the cylinder 22 a short distance to the right by application of pressure to the forming cylinders 28 and 30 at the connections C21 and C22. The exact distance of this movement is adjustable, and is determined by the limit switch LS (Fig. 2), as hereinafter more fully discussed. This movement is principally to relieve the longitudinal compressional stresses which operate upon the tubing when the convolutions are completed, and to permit the forming plates to be retracted. The book is then opened, after which the chuck is also opened.

The next step is the application of pressure to the forming cylinders 28 and 30 and to the pick-up cylinder 32, whereby the cylinder 22 is moved to its extreme left position, bringing the chuck face opposite the left end of the previously formed convolutions. The chuck is now closed on these convolutions, and the tube clamp is released, while the forming cylinders and pick-up cylinder are supplied with pressure to move the cylinder 22 to its extreme right hand position. The tube clamp is again closed, and the machine is in position for beginning the nextform'ing cycle.

When tubing of a sulficient length has been formed andit is desired to remove it from the machine, the pressure on the carriage lock cylinder 134 (Fig. 7) is removed, thereby locking the subcarriage 136 to the carriage. 126 by reason of the block 14-4- meshing with the rack 138. The chuck is then opened. Pressure is applied to the pistons 174 (Fig. 4) to unlock the sleeves 162 to permit the pistons 164 to slide toward the right in the cylinders 166. Pressure is then applied to the connections C3 and C4 (Fig. 4), thereby moving the carriage 126 to the right until it reaches the position shown in dash-dot lines in Fig. 5.

After the carriage 126 is moved to the right pressure is applied to the wheel operating cylinder 184, whereby the wheel 176 bears against the tube 110, or the completed convolutions of tubing thereon, to otter support at the left extremity. The formed tubing is then removed from the tube lit) over the top of the forming apparatus.

Next, the wheel 176 is lowered and the carriage 126 is moved back to its initial position by application of pressure to the connections C3 and C9 of the cylinders 166, whereby the carriage 126 is ultimately locked against the fixed post 6, the subcarriage 136 is disengaged from the carriage 126 (as shown in Fig. 6), and the sleeves 162 are securely locked to the cylinders 166 and rods 36, which move with the forming cylinders as indicated above. Thus, with the machine again in position for the forming operation, the rods 36 and the tube 116 are securely held together at their right extremities by connection to the support block 156, this block forming a slidable support which moves back and forth with the cylinder frame 26.

Operation controls The control apparatus for automatic, job, or single cycle operation will next be discussed with reference to Figs. 9, l0 and ll. In Fig. ll the hydraulic connections are shown in schematic form, with terminal connections C1, C2, C3, etc, which correspond to the hydraulic connectious discussed above with reference to Figs. 1 through 7. Several types of hydraulic valves are employed, and their ope-ration will be more readily understood with reference to the following description. Some of the valves are operated by solenoids, these being designated as V2, V311, V311, etc. All of these solenoids which operate hydraulic valves, as well as the magnet 520 shown in Fig. 5, are shown in Fig. 9. The contacts energizing the solenoids are numbered R2-1, R3-2, etc., the numbers referring to the relays shown in Fig. 10 The relays are numbered R1, R2, R3, etc., and each is provided with a number of contacts, each contact bearing the relay number, such as R1, followed by a hyphen and an arabie numeral distinguishing each set of cooperating contacts from every other set actuated by the same relay. In Fig. lb all relay contacts are shown in the positions reached when their corresponding relays are unenergized.

In addition to the relays and relay contacts, Fig. 10 shows a. number of control switches to be actuated by the machine operator, as well as limit switches, the physical positions of which are shown in Figs. l7. In Fig. 10 the limit switches are shown in their unactuated conditions. Two pressure switches PS1 and PS2, shown in their unactuated conditions in Fig. 10, are connected to the water pressure line as indicated in Fig. 11.

The operating switches of the machine comprise a master electrical power switch MS, an operating switch OS which is moved either to a run or load position as required, an automatic start switch AS, a stop switch SS, a job pre-set switch JP, a jog switch IS, an open chuck switch OCS, a closed chuck switch CCS, a single cycle switch SCS, and a single cycle pre-set switch SCP.

Provision for maintaining the fluid pressures necessary for the various operations is include in the controls. These pressures are normally allowed to build up before loading and operation, and are maintained throughout the operation at the desired levels. This may be illustrated by assuming certain initial conditions, and describing the successive steps thereafter in loading and operating the machine.

It is first assumed that no tubing is loaded into the machine, that the oil and water pumps are 011, that the piston operated valve VA1 (Fig. 11) is closed and a limit switch L815 actuated, that a hand operated valve VA2 is open as shown in Fig. 11, whereby a limit switch LS11 is actuated, that the switches JP and SCP are as shown in Fig. 10, that the switch OS is on load, and that the master switch MS is open. The first step is to close the switch MS. 7

Closure of the switch MS causes energization of the relays R14, R15, R19 and R11, which in turn energize the valve solenoids V14 and V11b.

Next, the oil and water pumps are started. The oil pump applies pressure moving an hydraulic booster piston 196 upward until a switch BS is opened. The switch BS is of the toggle type, whereby it is held in the position shown by a spring, but when the armature is moved a certain distance away from the stationary contact, the spring holds the armature away from the contact until an external force is again applied to close the contacts. When the switch BS is opened, the relays R14 and V14 are deenergized, whereupon the booster piston moves downward until the switch BS is again closed. This cycle repeats itself, building up water pressure in a line 198 until the pressure switch PS1 is actuated. Actuation of the switch PS1 energizes the relay R18 and deenergizes the relays R14, R15, and R19. The valve solenoid V14 is also deenergized, thus stopping the pumping action of the booster 196.

- By reason of the previous energization of the valve solenoid V11b, the starting of the oil pump also results in application of pressure to the connection C11, which closes the chuck, thereby first opening the limit switch LS16, and then closing the limit switch LS1. Pressure is also supplied to the connection C13 to unlock the tube clamp, and to a connection C15 of the cylinder 184 (Fig- 5) to hold the wheel 176 in its lower position. When the chuck is completely closed, the pressure in the line to the connection 011 builds up to a point where a relief, or sequence, valve is operated to apply pressure through a speed control, or throttle, valve to the connection C12, thus forcing the pick-up cylinder piston 24 to the right as shown in Figs. 1 and 2, thereby first deactuating the limit switch LS6 and then actuating the limit switch LS2.

The next step is to press and release the open chuck switch OCS. This energizes the relay R8 and the valve solenoid V8, putting pressure on the connection C18 to open the chuck, thereby first opening the limit switch LS1 and then closing the limit switch LS16. The relay RS holds after the release of the switch OCS through its contacts R8-1 and the momentary push-button switch CCS.

Next, a piece of tube stock is inserted into the machine a sufficient distance to pass beneath the chuck which is now open.

After the stockis inserted under the chuck, the switch CCS is depressed, deenergizing the relay R8 and the valve solenoid V8. Pressure is then applied to the connections C11 and C12 as above, whereby the chuck is closed and the pressure is reapplied to the pick-up cylinder piston, holding it in the position shown in Fig. 1.

With the machine loaded, the switch OS is next moved to'the run position, deenergizing the relay R11 and the valve solenoid V111), and energizing the relay R21 and the valve solenoid V6. 7

As mentioned above, the machine may be operated automatically, thatis, it may be operated so as to repeat the forming cycle without the intervention of the operaton The automatic operation is conveniently described in arbitrary steps as follows: a

'Step I.Th-is step is initiated by pressing and holding down the automatic start switch AS, which is shown in Fig. 10 as having two sets of contacts mechanically connected as indicated by the dash lines. This energizes the relays R-1 and R2 and the valve soleniods V2 and V3b, putting pressure upon a number of cylinders. as follows:

Pressure to the connection C11 holds the chuck closed, which corresponds to the limit switch LS16 being opened and the limit switch LS1 being closed. Pressure to the connection C12 holds the pick-up cylinder piston 24 to the right, which corresponds to the deactuation of the limit switch LS6 and the actuation of the limit switch Pressure to the connection C14 locks the tube clamp.

Pressure to the connection C15 holds the wheel 176 in the position shown in Fig. 5.

Pressure to the connections C21 and C22 moves the forming cylinders to the right. The limit switch LS3 is thereby closed, the limit switch LS5 is opened and the limit switch LS4 is actuated.

Pressure to the operating piston 200 of the valve VA1 holds closed the water pressure connection between the line 198 and the connection C10. The pressure is then applied through a sequence valve to a connection C25 to unlock the plates after the movement of the piston 200. Similarly, pressure is applied to a connection C24 to unlock the book frame after the plates are unlocked, if the indicated hand valve is open. However, as heretofore noted, this locking and unlocking device is optional for most applications, and in the present description it will be assumed that no lock for the book is employed. Upon the operation of a third sequence valve, pressure is finally applied to a connection C23 to open the book frame, thereby actuating the limit switches LS7 and LS8.

Step 2.-This step is initiated by releasing the start switch AS. The relays R3, R12, and R13 are then energized. This results in energization of the valve solenoids V3a and V13 and deenergization of the valve solenoid V3b, putting pressure on the connection C27 to close the book, thereby opening the limit switches LS7 and LS8 and dropping out the relay R12. The relay R13 holds through its contacts R13-1 and transfer contacts of the switch PS2. Operation of a sequence valve next closes the'spacers through application of pressure to the connection C29, thereby opening the limit switch LS9 and closing the limit switch LS10. This in turn energizes the relays R4 and R7 and the valve solenoid V4. Operation of a sequence valve then applies pressure to a connection C26 to lock the plates.

Step 3.This step begins with the energization of the valve solenoid V4 as described above. After the plates are locked, pressure is put on the operating piston 200 of the valve VA1 to put water pressure on to the connection C10. This actuates the pressure switch PS2.

Step 4.This step is initiated by actuation of the switch PS2. The relay R13 is then deenergized, thereby deenergizing the valve solenoid V13, and putting pressure on the connection C28 to retract the spacers. This results in opening of the limit switch L510, dropping out the relay R4 and the valve solenoid V4 to remove the pressure holding the valve VA1 open (but the valve VA1 stays open since there is as yet no pressure to shut it 01?); then, the limit switch LS9 is closed.

Step 5.This step begins with closure of the limit switch LS9. The relay R16 and the valve solenoid V16 are then actuated, putting pressure on the connections C19, C20 to move the forming cylinders to the left. This motion, first, deactuates the limit switch LS4, second, actuates the limit switch LS5 to energize the relay R5 and the valve solenoid V5, opening a by-pass path to the connections C19, C20, and last, actuates the limit switch LS3.

Step 6.This step begins with the actuation of the limit switch LS3. The relays R3 and R16 and the valve solenoids V3a and V16 are then deenergized-and the 11 valve solenoid V3b is energized, putting pressure on the connections C21, C22 and the piston 200. Pressure to the connections C21, C22 moves the forming cylinders to the right under the control of a throttle valve in the line which has been opened by energization of the valve solenoid V5. This motion continues until the limit switch LS5 is deactuated; whereupon, the relay R5 and the valve solenoid V5 drop out to prevent further motion to the right. Pressure to the piston 200 turns the water valve VA1 off, thereby deactuating the switch PS2. Pressure is then applied to the connection C25 to unlock the plates, and finally to the connection C23 to open the book, thereby actuating the limit switches LS7 and LS8.

Step 7.This step begins with actuation of the limit switches LS7 and LS8. The relays R8, R11 and R12 are energized. The valve solenoids V8, V11a and V111) are also energized, putting pressure on the connection C18 to open the chuck, which first opens the limit switch LS1, then closes the limit switch LS16.

Step 8.This step begins with closure of the limit switch LS16. Pressure is then applied to the connection C17 to move the pick-up cylinder piston 24 to the left, which first opens the limit switch LS2, then actuates the limit switch LS6. At the same time, the relay R16 and the valve solenoid V16 have been energized by closure of the switch LS16, which puts pressure on the connections C19, C20 to move the forming cylinders to the left, which in turn first closes the limit switch LS5, then opens the limit switch LS3.

Step 9.This step begins with the actuation of the limit switch LS6. The relay R9 is then energized, holding through its contacts R94 and the limit switch LS4, and the relays R7, R8, R11, R12 and R16 are deenergized. The valve solenoid V8, Vlla, V111), and V16 are also deenergized, putting pressure on the connections C21 and C22, and tending to move the forming cylinders to the right, but no motion occurs because there is no exhaust outlet at this time for the connections C19, C20. At the same time that pressure is applied to the connections C21, C22, it is also applied to the connection C11 to close the chuck, thereby first opening the limit switch L516, then closing the limit switch LS1. A sequence valve then applies pressure to a connection C12 to move the pick-up cylinder piston 24 to the right, thereby first deactuating the limit switch LS6, then closing the limit switch LS2.

Step 10.-This step begins with the deactuation of the limit switch LS6. The relays R5, R6, R10, R12 and R17 are energized, and the valve solenoids V5 and V10 are energized while the solenoid V6 is deenergized. This puts pressure on the connection C13 to unlock the tube clamp and also furnishes two exhaust paths to allow movement of the forming cylinders to the right by reason of the pressure then being applied to the connections C21, C22, which first closes the limit switch LS3, then opens the limit switch LS5, and finally actuates the limit switch LS4. The opening of the limit switch LS5 drops out the relay R5 and the solenoid V5, but this does not impede the rightward movement of the forming cylinder since a parallel path to the exhaust is available.

Step 11.This step begins with the actuation of the limit switch LS4. The relays R9 and R10 are deenergized, while the relays R13 and R3 are energized. The valve solenoids V3b and V10 are deenergized and the valves V3a and V13 are energized, putting pressure on the connection C27 to close the book, thereby opening the limit switches LS7 and LS8 and dropping out the relays R6, R12 and R17, but not affecting the relay R13 which holds through its contacts R13-1 and the switch PS2 transfer contacts. Deenergization of the relay R6 causes energization of the solenoid V6. Pressure is then put on the connection C14 to lock the tube clamp and on the connection C29 to insert the spacers, thereby opening the limit switch LS9 and closing the switch LS10, which energizes the relays R4 and R7 and the valve solenoid V4.

Thereupon, pressure is applied to the connection C26 to lock the plates.

Step 12.This is the same as step 3 described above.

To stop the automatic operation, the switch SS is depressed. This opens the holding circuit for the relay R1 which includes the contacts R21-1, R11 and the switch SS. Opening of the contacts R12 then deenergizes the relay R2 and the valve solenoid V2. The result is that no power can reach the relay circuits through the lower contacts of the switch AS until that switch 'has again been depressed and released, and no pressure transfer can be effected to operate the forming cylinders or the various cylinders for operating the book, plates or spacers, or the water valve VA1. To remove the formed tubing from the machine after stopping the automatic operation, the switch 05" is first thrown to the load position and then the switch OCS is depressed. This energizes the relay R8 and the valve solenoid V8, putting pressure on the connection C18 to open the chuck, as described above.

Automatic operation may also be stopped by closing the manual valve VA2. This actuates the limit switch L812, thereby energizing the relay R15. Relay R15 opens its normally-closed contacts R15-1 and causes deenergization of the relay R1. Thus, the same elfect is produced as if the switch SS had been depressed.

The controls are also adapted to furnish protection by stopping the automatic operation if the tubing bursts under the water pressure at any time during the forming cycle. This is also accomplished by the relay R15 through the opening of its contacts R154. In this case the relay becomes energized through the contacts R19-1, L515 and the pressure switch PS1 which becomes deactuated by reason of the loss of pressure in the line 198. The contacts R19-1 are closed by energization of the relay R19 as a result of the deactuation of the switch PS2. The limit switch L815 is closed on the subsequent closure of the valve VA1.

The machine may be easily switched to jog operation, by which it continues to follow the automatic cycle heretofore described, but only as long as the jog switch 15 is held depressed. The jog pre-set switch JP is first thrown to the other position from that shown in Fig. 10. This opens the holding circuit of the relay R2 so that the relay R2 will operate only while the switch I S is held depressed. Whenever the switch JS is released the relay R2 and the valve solenoid V2 are deenergized and the same hydraulic connections are cut off as when the switch SS is depressed. In other words, the automatic cycle is effective at all times while the switch JS is depressed, but the machine may be stopped at any point in the cycle by releasing this switch.

For single cycle operation the switch SCP is first thrown to the other position from that shown in Fig. 10. The cycle is then initiated by first depressing and holding the switch SCS while depressing and releasing the automatic start switch AS. As soon as the switch AS is released, the switch SCS may be released, and the machine will then perform one full cycle and stop.

It will be understood that while the invention has been described with reference to a preferred embodiment, numerous modifications in the structure and in the control of the various operations thereof may be made in accordance with principles and techniques already familiar to thoe skilled in this art, and that such modifications would not constitute a departure from the spirit or scope of the invention.

Having thus described the invention, I claim:

1. Apparatus for forming flexible tubing having, in combination, a pair of clamps for the tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each. of said, shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space 13 through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, and means for completing said convolutions by moving the clamps together while said pressure is maintained,

' the shafts being adapted to slide upon one another and shafts to form partial convolutions by bulging the tubing outwardly against the plates, means for removing the spacers from between the plates, and means for completing said convolutions by moving the clamps together while said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed.

3. Apparatus for forming flexible tubing having, in combination, a fixed clamp and a movable clamp for the tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each of said shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, and carriage means operatively connected with one of the shafts and the movable clamp for moving the clamps and seals together to complete said convolutions whle said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed.

4. Apparatus for forming flexible tubing having, in combination, a fixed clamp and a movable clamp for the tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each of said shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, carriage means operatively connected with one of the shafts and the movable clamp for moving the clamps and seals together to complete said convolutions while said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed, means to release said pressure, and means operable upon release of the pressure to separate the clamps a predetermined amount while maintaining engagement with each end of the formed tubing.

5. Apparatus for forming flexible tubing having, in combination, a fixed clamp and a movable clamp for the tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each of said shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, and carriage means to support one of the shafts, said carriage means having latching means engageable with the movable clamp for moving the clamps and seals together to complete said convolutions while said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed, said latching means being disengageable from the movable clamp,

the shafts from within the clamps.

6. Apparatus for forming flexible tubing having, in

combination, a fixed clamp and a movable clamp for the tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each of said shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, a carriage to support one of the shafts, a subcarriage movable on said carriage to support the other shaft, the sub-carriage having latching means engageable with the movable clamp and means for moving relative to the carriage to move the clamps and seals together to complete said convolutions while said pressure is maintained,

the shafts being adapted to slide upon one another and,

to maintain said space closed, and means for disengaging said latching means from the movable clamp and engaging said carriage and sub-carriage, whereby the carriage may be moved to withdraw the shafts from within the clamps.

7. Apparatus for forming flexible tubing having, in combination, a tube clamp adapted to engage straight tubing and a chuck clamp adapted to engage formed tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each of said shafts having a fluid seal whereby a closed spacemay be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, means for completing said convolutions by moving the clamps together while said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed, and pickup means to release said seals and clamps and to engage the chuck clamp with the convolutions thus formed to introduce a new section of tubing between the clamps.

8. Apparatus for forming flexible tubing having, in combination, a fixed tube clamp adapted to engage straight tubing and a movable chuck clamp adapted to engage formed tubing, two concentric hollow shafts to be received inside the tubing through one of the clamps, each of said shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, spaced forming plates adapted for closing around the tubing in the region of said space, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the plates, a carriage to support one of the shafts, a subcarriage movable on said carriage to support the other shaft, the sub-carriage having latching means engageable with the chuck clamp and means for moving relative to the carriage to move the clamps and seals together to complete said convolutions while said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed, pickup means to release the seals and clamps and to engage the chuck clamp with the convolutions thus formed to introduce a new section of tubing between the clamps, and means for disengaging said latching means from the movable clamp and engaging said carriage and sub-carriage, whereby the carriage may be moved to withdraw the shafts from within the clamps.

9. In flexible tube forming apparatus, the combination of a fixed clamp to hold an unformed section of tubing, and an assembly comprising hinged end plates movable axially with respect to the tubing, hinged forming plates having graded steps slidably supported between the end plates and adapted for closing around the tubing, and stepped plates arranged to engage the steps of the forming plates including a plate secured to the end plates to 15 limit the movement of each forming plate in one direction relative to the end plates and a plate adapted to limit the movement of each forming plate in the reverse direction relative to a fixed position.

10. Apparatus for forming flexible tubing having, in combination, a fixed clamp to hold an unformed section of tubing, an assembly comprising hinged end plates movable axially with respect to the tubing, a clamp for the tubing movable with said end plates, hinged forming plates having graded steps slidably supported between the end plates and adapted for closing around the tubing, and stepped plates arranged to engage the steps of the forming plates including a plate secured to the end plates to limit the movement of each forming plate in one direction relative to the end plates and a plate adapted to limit the movement of each forming plate in the reverse direction relative to a fixed position, two concentric hollow shafts to be received inside the tubing through the movable clamp, each of said shafts having a fluid seal whereby a closed space may be formed in the tubing between the clamps, means for applying hydraulic pressure to said space through the inner of said shafts to form partial convolutions by bulging the tubing outwardly against the forming plates, and means for completing said convolutions by moving said assembly toward the fixed clamp while said pressure is maintained, the shafts being adapted to slide upon one another and to maintain said space closed.

11. A method of forming flexible tubing consisting of the steps of externally clamping a longer length of straight tubing at two separated positions along its length, sealing a space within the tubing between said positions, applying hydraulic pressure to said space while externally restraining the tubing annularly at uniformly spaced intervals between said positions, compressing the tubing to decrease the distance between said positions while retaining said pressure and annular restraint, releasing said pressure, annular restraint and clamping, and moving the section of convolutions thus formed longitudinally to permit clamping a new section of unformed tubing.

12. A method of forming flexible tubing consisting of the steps of externally clamping a longer length of straight tubing at two separated positions along its length, sealing a space within the tubing between said positions, applying hydraulic pressure to said space while externally restraining the tubing annularly at uniformly spaced intervals between said positions, compressing the tubing to decrease the distance between said positions while retaining said pressure and annular restraint, releasing said pressure, expanding the tubing by a predetermined distance, releasing said annular restraint and clamping, and moving the section of convolutions thus formed longitudinally to permit clamping a new section of unformed tubing.

References Cited in the file of this patent UNITED STATES PATENTS 1,689,620 Clifford Oct. 30, 1928 2,028,150 Grant Jan. 21, 1936 2,080,211 Mantle May 11, 1937 2,306,018 Fentress Dec. 22, 1942 2,581,787 Dreyer Jan. 8, 1952 

